The present invention relates to a band saw, and in particular to a band saw for sawing logs with the grain (band resaw) or for dividing wood blocks, the band saw being of the kind which comprises upper and lower band pulleys which can be adjusted in relation to one another and over which there extends an endless band-like saw blade which is driven by one of the band pulleys, and in which saw the lower pulley is journalled in a frame structure which can be moved axially along two mutually parallel guides extending at right angles to the feed direction of the material to be sawn, and in which the other pulley is mounted on the upper end of a post located on the frame structure.
Such band saws are known from, for example, our Swedish Patent Specification No. 7312757-3. Although band saws of this kind are found to function satisfactorily, they are nevertheless encumbered with certain structural drawbacks, of which the following are examples. When combining the saw with chipper devices, located immediately upstream of the saw blade and intended to cut peripheral log portions into cellulose chip form, an obstacle is presented which disturbs the downward passage of the chips into an underlying collecting receptacle. In addition, the known saws are extremely heavy and require a relatively large amount of space.
These drawbacks are at least partly due to the fact that the two guides of the known saw construction are placed in juxtaposition in a mutually common horizontal plane. As a result hereof, when the saw is combined with a disc chipper the guide located furthest from the saw blade presents, inter alia, an obstacle to the passage of chips into the underlying chip collector. This juxtaposed relationship of the guides also widens the saw frame unnecessarily in the horizontal plane, thereby increasing the space required. This conventional positioning of the guides also means that the guide located beneath the upper pulley post supports substantially the whole weight of the saw, whereas the other guide is relied upon to prevent tipping. As a result of these additional functions of the guides, the guides are given dimensions and weights greater than would be necessary if it were possible to distribute the weight of the saw uniformly between the two guides. The asymmetric weight distribution on the two guides can also lead to other drawbacks.